box design please (willing to pay if needed)

[qcbangin]

I got a pair of old school powerbass pbx 12's in a prefab box in a trade. Went to a local db drag this past weekend and ran for shits and giggles. Believe it or not, they hit a 141.5@47hz! I didn't plan on keeping them at first, but that changed my mind. Now, I'm looking for a design for these and see what they can do in a proper box. I'm willing to pay for a design if I need to.

Car:1996 chevy cavalier 4 door

Amp will be a hifonics bxi2610@1ohm

They have to be in the trunk, but seat folds down so they can fire forward sealed off if necessary.

Dimensions of the trunk:

17.5"H

18.5W

29"D

Not a lot of room, but I can build the box in the trunk if I have to, or I can also put it in through the back seat.

Any help, advise, or a design will be greatly appreciated. And as the title says, I can pay for a quality design.